The present invention relates to an operation method and an operation control device for a servo press line in which a servo press and a servo transfer device are alternately disposed in the workpiece transfer direction.
A servo press line has been known in which servo presses and servo transfer devices are alternately disposed in the workpiece transfer direction. The servo press presses a workpiece transferred from the upstream-side servo transfer device. The downstream-side servo transfer device transfers the pressed workpiece from the servo press. The upstream-side servo transfer device and the downstream-side servo transfer device respectively refer to the servo transfer device that is disposed adjacent to the servo press on the upstream side of the servo press in the workpiece transfer direction, and the servo transfer device that is disposed adjacent to the servo press on the downstream side of the servo press in the workpiece transfer direction. The workpiece is pressed by the servo press while being sequentially transferred by the servo transfer device in the downstream direction to obtain a product.
In this case, it is necessary to control the motion of the servo press (i.e., slide and die), the motion of the upstream-side servo transfer device, and the motion of the downstream-side servo transfer device so that the servo press, the upstream-side servo transfer device, and the downstream-side servo transfer device do not interfere with each other. For example, JP-A-2008-137015 discloses a technique that prevents interference by synchronizing the position of the slide of the servo press and the position of the servo transfer device with a master signal.
The servo press line is required to prevent interference even when an abnormality has occurred in the servo press or the servo transfer device. The technique disclosed in JP-A-2008-137015 decelerates or stops all of the servo presses and all of the servo transfer devices when an abnormality has occurred while maintaining synchronization by changing the rate of the master signal, or setting the rate of the master signal to 0.
JP-A-2009-285666 discloses a technique that supplies power through a bus that can supply regenerative power when a power failure has occurred. The technique disclosed in JP-A-2009-285666 decelerates or stops all of the servo presses and all of the servo transfer devices while maintaining synchronization by changing the rate of the master signal, or setting the rate of the master signal to 0, using the supplied power.
JP-A-2010-12511 discloses a technique that prevents interference by performing a correction control process when the motion of the servo press or the servo transfer device has advanced or delayed.